<p>Artificial intelligence is founded on the premise that all cognitive activity can be explained in terms of computation. This premise has a long and illustrious tradition in Western philosophy, starting with Aristotle and Plato, and the advent of computers and the progress made in symbolic computation led to a new branch of computer science. AI's scientific goal is to understand the principles and mechanisms that account for intelligent action. The allied engineering goal is to design intelligent artifacts that can survive and operate in the physical world and solve problems of considerable scientific difficulty at high levels of competence. AI is primarily an empirical science, in which researchers use classical hypotheses and test research paradigms to validate these models and mechanisms. The computer is the laboratory where AI experiments are conducted.</p>